The Significance of the Hockey Stick

Recently, as the hockey stick looks more and more splintered, some climate scientists have argued that the hockey stick graph was merely incidental in Kyoto promotion.

As someone with actual experience in business promotions, this proposition has seemed peculiar to me, since the hockey stick graph was displayed so prominently by IPCC. This view was re-inforced by an interesting essay by David Deming here.

To understand the role of the hockey stick in Kyoto promotion, one need look no further back than the IPCC Second First Assessment Report in 1995 1990 [Update 2012: see discussion here where I diagnosed the provenance of the IPCC 1990 Figure 7c. At the time of my 2007 post, William Connolley, for example, had stated on his blog that it lacked a “good source”, a remark which occasioned my own subsequent analysis of its provenance in 2008. ]

The millennium temperature history portrayed in that report is shown in the diagram below.

Simply looking at this diagram shows the problems that IPCC promoters would have. You couldn’t sell the public with this graphic.

Deming’s essay summarize the problem for climate promoters at the time:

…With the publication of the article in Science, I gained significant credibility in the community of scientists working on climate change. They thought I was one of them, someone who would pervert science in the service of social and political causes. So one of them let his guard down. A major person working in the area of climate change and global warming sent me an astonishing email that said "We have to get rid of the Medieval Warm Period."

Deming goes on to discuss Nature‘s biased handling of an important paper by Huang in 1997.

In 1998, there seems to have been a bit of a race between the Mann, Bradley, Hughes group in the U.S. and the Jones, Briffa group in the U.K. to be the victor in getting rid of the MWP, with both groups publishing multiproxy studies.

Obviously, MBH98/99 got featured, with Jones et al [Holocene 1998], which offered less dramatic statements, getting shuffled to a secondary role, included in spaghetti diagrams, but not in the main promotional diptych. Of course, the other half of the main promotional diptych was Jones’ temperature history, so both groups got a piece of the promotion.

For me, the picture below – John Houghton in front of the hockey stick diagram – represents the end result rather nicely.

When I showed this picture to the Toronto Geological Discussion Group, all familiar with mining promoters, it was impossible to avoid comparing Houghton to mining promoters that we know.

I’ve sat through a number of well-attended public symposia at the University of Victoria where climate scientist (and IPCC member) Andrew Weaver was speaking, and I recall that the Hockey Stick featured prominently at most or all of them. IIRC, Weaver would use several overlays to "prove" the reality of climate change: one to represent what "natural climatic variability" would have been in the absence of anthropogenic CO2; one to represent climate if CO2 was the ONLY contributor to warming; and one to show how nicely the two previous overlays added together to make the Hockey Stick. (Weaver is a funny bird–on one hand, he is properly dismissive of the alarmist scenarios that too often surround discussions of climate change; on the other, he persists in the brain-dead rhetorical device of portraying climate skeptics as tools of the fossil fuel industry or otherwise morally compromised.) Not to mention the use of the Hockey Stick in countless smaller seminars in my field at the time (energy systems), when the speaker wanted to represent climate change in a visual shorthand that the audience was sure to comprehend. Not to mention its use in undergraduate energy systems classes, when the professor wanted to scare the students about the inevitability of catastrophe unless we moved to a hydrogen economy. Not to mention its Forrest Gump-like appearance in virtually every illustrated media story on climate change that I have seen.

It’s easily the most popular climate change-related graphic out there. What else even comes close? If it falls (as is looking increasingly likely), the IPCC loses its most powerful tool for persuading the public of the case for drastic action.

Steve: I like the Forrest Gump image. I recently had some correspondence with Andrew Weaver, who has become editor of Journal of Climate, and who was the editor for Rutherford et al. [2005], which was discussed in realclimate as purporting to “discredit” all our findings. I’ve posted some comments on this earlier. There is nothing in Rutherford et al [2005] about principal components methodology; instead they recycled comments from Mann’s November 2003 Internet article criticizing MM03 for not implementing a previously undisclosed stepwise method (which was itself a diversion from the uncentered issue). So I wrote to Weaver and said that, if Mann is purporting to rebut our comments, then he should be discussing up-to-date principal components issues (which were even being discussed on realclimate). I noted that the referee might not be familiar with these matters, but there was an obligation on Mann to disclose these problems. I distinguished between “full, true and plain disclosure” and “don’t ask- don’t tell” disclosure, which seemed to be what Mann was doing and suggested that Weaver ask for certification of full, true and plain disclosure and re-referee the points in question. He wrote back that the authors “stood behind” what they had written, which seemed to satisfy him. Although Weaver was editing this article, when he talked to the National Post, and even a little while later, had not taken the time to read our critique of Mann’s PC methods., which seems a little odd, since he was editing an article, which made a point of stating that it was rebutting our claims.

That’s a nice little bit of sleight-of-hand pulled by John Hunter in his PDF: using the SPM of the TAR to gauge the "influence" of the Hockey Stick. Virtually no-one has read the SPM (not even, one suspects, most policymakers)–yet the Hockey Stick features prominently in all manner of scientific, technical, environmental, governmental, and other popular treatments of climate change. Now how did THAT happen? I can only vaguely recall a few graphics from the TAR offhand (the "climate forcing uncertainty" bar chart being one), but the Hockey Stick is clear, having been reinforced in countless viewings outside of the TAR in all sorts of contexts. Honestly, climate scientists don’t do much to help themselves when they release junk like Hunter’s.

Steve: The hockey stick was not incidental; it was front and center. When a business promotion goes south, it’s the false statements and misrepresentations that people get mad about.

What makes this affair particularly bad in my opinion is that there is evidence that material results were withheld (e.g. the R2 statistic which shows negligible statistical significance), that a series was “edited” to ensure that 15th century results did not exceed 20th century results (without reporting this), and that there were a number of misrepresentations: of robustness, of the methods used etc .

The article by Prof. Deming reminds me of the story of Han van Meegeren – a Dutch forger – who in the 1930s painted a “Vermeer” (‘The Supper at Emmaus’) that the critics thought was the ‘missing link’ in the work of Vermeer. It was a perfectly fitting piece of the Vermeer style puzzle the art experts had been trying to solve during their careers.

Han van Meegeren probably wouldn’t have been caught if he wasn’t forced to prove his innocence of selling a “Vermeer” to a top Nazi by showing he painted it himself.

(I would like to stress I am not implying that Prof. Mann is a fraud. I am just trying to present a case in which many people accepted something so eagerly – potentially at high cost).

It is interesting to read the totally unsupported claims that seem to pop up on this site. Murray Love said (posting 5): "Virtually no-one has read the SPM (not even, one suspects, most policymakers)" — really? — presumably Murray had done research on this that he would like to share with us — or perhaps allow us to audit? And there I was thinking that the contrarian party line was that the only thing non-scientists ever read WAS the SPM, which is of course a sad travesty of the science in the rest of the IPCC report …..

Murray then goes in standard contrarian style to dismiss all that he doesn’t like as "junk" with: "climate scientists don’t do much to help themselves when they release junk like Hunter’s". Pray, Murray, tell us why it is "junk" — now don’t just do an M&M on it (i.e. only pick holes in it) — if you think I did the analysis wrong please come up with a better one (and I am sure there is, but I am also pretty sure that it would come up with effectively the same result).

It is also hard not to comment on the customary incisive wit and intelligence of "John A", whose sole contribution to this discussion has been: "..which is obviously irrelevant since its more than six days old. ….. That picture of John Houghton in front of the Hockey Stick always looks like lightning is hitting the old man’s forehead. It would explain a lot." (and extra marks for a bit of good old fashioned ageism — what century does "John A" come from?).

Steve: I know it is hard to find good service nowadays, but can’t you really do any better than this?

John replies: Thank you for that detailed and thorough analysis of the underlying statistical treatment of Mann, Bradley and Hughes (1999), and its implications for public environmental policy. Without your deep insight into the mathematical subtleties of Principle Component Analysis and the inherent uncertainties into dendrochronology, we would all be the poorer, and this weblog ignored by the “movers and shakers” of climate science. How refreshing it is to have someone like yourself, tearing themselves away from their critical work in climate science, to be able to spare us a few scattered pearls of your impressive philosophical wisdom.

John: I’m not sure if you are the same as “John A” but you both seem to think that pathetic attempts at humour are a substitute for actually answering the questions in hand. This thread is headed “The Significance of the Hockey Stick”, and the main “article” is about the presumed “promotion” of the hockeystick by the IPCC and others. It is NOT about “he underlying statistical treatment of Mann, Bradley and Hughes (1999)” or “mathematical subtleties of Principle Component Analysis and the inherent uncertainties into dendrochronology”. It contains three postings which refer directly to my short article at http://www.antcrc.utas.edu.au/~johunter/ipcc_stats_2.pdf. I was responding to these postings (i.e. not just parroting the alleged findings of M&M which seems to be the norm on this site). So, if you are going to contribute at all, why do you not address the issue that is actually being discussed?

I thought my meaning was clear, but perhaps not. Your analysis is not junk because it is statistically unsound (I can’t be bothered to check, since it’s beside the point); it is junk because it so obviously (and, I suspect, deliberately) misses the point.

Your attempt to prove the relative insignificance of the Hockey Stick is based solely on the weight given to it in the SPM of the TAR–a document that relatively few people have read, including, I suspect, most policymakers. [Emphasis added, since you seem to have missed my caveats the first time round]. Since–as your argument goes–it is given relatively little weight in the SPM, it follows that it has had correspondingly low influence.

But your argument is an obvious strawman, eminently deserving of the “junk” label. The Hockey Stick has become THE emblematic representation–a logo of sorts–of climate change science, entirely unmoored from its ostensibly humble and cautious origins in the TAR. It pops up behind John Houghton, in IPCC climatologist Andrew Weaver’s lectures and public seminars, in all manner of government-sponsored climate change propaganda, in environmental advocacy literature, in media reports, you name it. It is immensely influential, and its discrediting would deprive climate change advocates of a powerful propaganda tool.

If you still have trouble understanding this rather elementary point, here’s an analogy: I could claim–per Hunter–that based on a statistical analysis of the proportion of biblical verses devoted to it, the story of (say) David and Goliath has been insignificant to western culture. Of course, I would have to boneheadedly ignore the mountains of references to it in all manner of literature, its use in religious ceremonies as an example of the power of the Judeo-Christian God, its common use as an all-purpose underdog metaphor, and so on.

But look at me–I’m just repeating the basic argument I made in my first post; and when I find myself doing that, it’s usually because my opponent hasn’t added anything new to the discussion. To quote you back at yourself, “[t]his thread is headed ‘The Significance of the Hockey Stick’, and the main ‘article’ is about the presumed ‘promotion’ of the hockeystick by the IPCC and others [scare quotes yours, emphasis mine]”. By focusing solely on the SPM of the TAR, you have done nothing to address its near-ubiquity in popular treatments of climate change. Care to try again?

Murray Love: Firstly, I love the way you change history. Your earlier statement “virtually no-one has read the SPM” has now become “….. the SPM of the TAR — a document that relatively few people have read”. I think these say different things, don’t you?

Next, you say “By focusing solely on the SPM of the TAR, you have done nothing to address its near-ubiquity in popular treatments of climate change. Care to try again?”. No thanks — I’ll leave that to you — and if you DO do it, then please do it quantitatively and don’t just cherry-pick. I assume that my own article was relevant to the Steve’s original article as it was brought up by David H in the very first posting (note that I had nothing to do with it being introduced into the present discussion). My article dealt with ONE aspect of the Steve’s article, which was the presumed promotion of the hockeystick by the IPCC, and I showed it to be untrue. That doesn’t mean I automatically have to deal with every other issue raised by Steve’s article, does it?

John Hunter, the issue is whether the IPCC used the hockey stick for its promotions. It did. Your calculations fail to disprove this obvious point. You showed nothing in my posting to be “untrue”.

In a prospectus, you can’t have ANY material misrepresentations. This is obviously not the case either with MBH98 or IPCC TAR. Given the prominence of the hockey stick in promotions, this was a very material representation.

If you look at Enron’s financial statements, not everything in them was false. But obviously some big things were false in their contingent liabilities. Using Hunter principles of print space, a Hunter audit of Enron would conclude that the financial statements were fine. Hunter principles applied to climate science are surely a big part of the problem.

It’s true that I misquoted myself back there, as I realized with some embarrassment afterwards; however, my point still stands, and your argument is as weak as ever. I stand by my contention that very few people have read the SPM (let alone the TAR), and I’d venture to say that your razor-sharp statistical analyses might be better employed by standing on a street corner and confirming this for yourself. Heck, get your grad students to do it–that’s what they’re for, after all. You could then have them perform an even more sophisticated analysis by measuring the recognition of the Hockey Stick among those who have not read the SPM or the TAR. It’s obvious that the second number will be far higher than the first; the only question is by how much.

Your analysis might have had some merit if Steve had restricted his claim about the IPCC’s “promotion” of the Hockey Stick to the TAR, and if IPCC luminaries such as John Houghton, Andrew Weaver and others hadn’t helped to make it the logo of anthropogenic climate change by featuring it prominently in lectures and press conferences, and if Kyoto promotion was limited to the IPCC alone, rather than all manner of other vested interests in governments and NGOs worldwide.

By the way, I note that you may have changed your analysis since my original posting–the date now reads 23/3/2005. Since I didn’t keep a copy of the original, I cannot tell if anything material has been changed.

Picture the scene, the International Pillar Construction Company (IPCC) decide to build a circular tower made of bricks provided by various brick-making companies around the world. The brick tower will be over sixty feet tall, from 180 rows of bricks each four inches tall.

Three of the rows of bricks are provided by Michael Mann Brick and Hod Incorporated (MBH), and these bricks are located near the base of the tower. Half way into the build, retired clay miner Stephen McIntyre comes on to the building site. “We must stop the construction”, Stephen warns, “there is a flaw in the manufacture of Michael Mann’s bricks. They will not support the full weight of the tower.”

Whispers, debate and discussion circle the building site. What will be done? Outside observer John Hunter comes to the rescue with a short note.

“It’s all okay”, says John, “I’ve done some analysis. Even if the bricks do fail, they represent just 1.667% of the tower, to four significant figures. There is no problem.”

All characters in this analogy are fictional and any similarity to persons or organisations in real life are entirely coincidental.

Murray Love and Spence_UK: You still seem to miss the rather important point that my article was NOT written to address Steve’s article which heads this thread. So Murray’s statement that “your analysis might have had some merit if Steve had restricted his claim about the IPCC’s “promotion” of the Hockey Stick to the TAR …..” is irrelevant. If you object to my analysis being brought into this thread, then complain to David H who introduced it. And Spence_UK — your analogy is fatuous — you first have to prove that the MBH “brick” is fundamental to the theory that we are undergoing global warming, a significant part of which is caused by human activity (see http://www.realclimate.org/index.php?p=114 for some help on this).

And Murray asks “by the way, I note that you may have changed your analysis since my original posting …”. No — I have clarified the text in line with some comments I received. The analysis is the same. I am tempted to quote John Maynard Keynes: “When the facts change, I change my mind – what do you do, sir?”, but I won’t as I haven’t changed my mind — I’ve just listened to other people and made what I think are useful changes.

John Hunter: Your ‘analysis’ concludes “It seems quite clear from the diagram that the Mann et al. reconstruction was not the “cornerstone” of the case for anthropogenic global warming made by the IPCC TAR. It was just one small (but nevertheless important) contribution.”
That is rubbish.
The case for global warming being anthropogenic rather than natural in origin rests on the assumption that recent warming is unprecedented i.e. it cannot be ascribed to natural fluctuations. The only historical ‘evidence’ presented by the IPCC for the unprecedented nature of recent warming is Mann et al.
Mann et al. is thus an IPCC ‘cornerstone’ and rather than just a brick, I would say it is just about the whole foundation.

So when the TAR was produced the IPCC considered Mann’s work to be one of the five most important graphs to be shown in all of the work collated in the years leading up to it.

Why? Well, because the Mann hockey stick and the Vostok ice core records make the most convincing selling point for anthropogenic global warming – both show flat lines followed by an unprecedented acceleration upwards.

The fact that the hockey stick is merely an artefact of bad statistical practices, and the Vostok ice core records, although I would make no criticism of the science, are being used outside their limitations, appears to be of no concern to the IPCC. They just want to make the sale. (Limitations of ice core record: they average CO2 concentration over centuries, unlike the leaf stomata used by Wagner et al, who point out in decadal terms, 300+ppm CO2 concentrations are the norm in the holocene)

The IPCC TAR SPM is not a scientific document, it is a sales pitch, it is selling the anthropogenic global warming story to the international governments, who then sell on to the public. The tower in my analogy is one of public opinion, and the Mann hockey stick is the cornerstone of the sales pitch.

My analogy is not perfect – analogies very rarely are – and I tend not to use them, except when presented with severe obfuscation, such as in this case. But the analogy is not fatuous in the way you suggest.

As you can see, anyone can play at these numbers counting games. But at the end of the day Steve’s observation is the most important: very bad science was included in the single most important report generated by the IPCC to date. Putting the error in slightly smaller print doesn’t make it right.

Your "rather important point" rather appears to be a distinction without a difference. Your analysis claims that "[s]ome have suggested" that the IPCC made the Hockey Stick the "cornerstone" [your quotation marks] of their case in the TAR , without citing any of those who have made this specific suggestion. I am certain that such a claim exists somewhere, but all the criticisms I can recall seeing relate to the Hockey Stick’s prominence in public climate change advocacy, whether by IPCC members or others.

So, here’s where we’re at: If we disregard the fact that the Hockey Stick was somehow chosen to be among the elect 2.4% of TAR figures chosen for inclusion in the SPM (assuming Spence_UK’s figures are correct), and that it has a habit of popping up in an astonishing number of non-SPM places, your analysis is making a very minor point indeed: to wit, those who suggest that the Hockey Stick is given too much prominence in the SPM may be overstating their case a little. I do apologize for doubting you.

Oh, and that Keynes quote? I haven’t changed my mind on anthropogenic climate change (relentless agnostic, expecting surprises), but I have changed my mind on the Hockey Stick–as much from the remarkably evasive–dare I say unscientific?–behaviour of its creators as from the interesting analyses of Messrs M&M.

> To understand the role of the hockey stick in Kyoto promotion, one need look no further back than the IPCC Second Assessment Report in 1995. The millennium temperature history portrayed in that report is shown in the diagram below.

Deming’s odd essay, which you recommend, also makes no sense when you know about the 1995 report.
Steve: the 5 in 1995 was struck out. However, for greater clarity, I’ll insert a space. Nor did this post “recommend” Deming’s essay: it referred to it. It is possible to refer to documents without “recommending” them – indeed, I’ve referred to your blog posts from time to time.

While we’re tidying old posts, perhaps you can include a link to my identification of the provenance of IPCC Figure 7c (https://climateaudit.org/2008/05/09/where-did-ipcc-1990-figure-7c-come-from ) at your blog at which these matters were discussed, since, as far as I can tell, my blog post was then the first proper identification of the provenance of this figure, the provenance of which then stumped you.

Further, it is clear from blemishes and other alterations in the image you used in 2005 that the image you posted (and which can still be found above) was that posted by John Daley on his website in 2001. As John Daley corrected his attribution in 2004, a year before you misattributed the image, presumably you did not get the image directly from Daley or his website, but from some other person. Would you care to clarify who first brought the image to your attention, and in what context?

I note that proper attribution involves attribution of secondary sources rather than primary sources when you use the secondary source rather than the primary source, as you clearly did not do in this case.

Steve: William Connolley’s precise words at the time were that the graphic lacked a “good source”. In deference to your comment, I’ve slightly amended my update comment to quote directly from Connolley. As you observe, the Climategate emails show that Connolley himself was aware that the graphic originated from Lamb though he did not say so on his blog and the statement at his blog was somewhat of a misdirection given his actual knowledge.
I don’t recall where I picked up the version used in the post. You say that Daly “corrected his attribution in 2004” – do you have any evidence for this other than the fact that his attribution in 2004 (http://www.john-daly.com/hockey/hockey.htm) was correct? Why do you believe that Daly didn’t have a correct attribution all along? It looks to me like the incorrect attribution to IPCC 1995 in my March 2005 blogpost was my own slip, rather than something that I inherited from another commentary. Deming’s article, cited in my 2005 blogpost, got the 1990 attribution right for example. As I noted previously, I crosschecked the origin soon afterwards and all attributions after June 2005 were to IPCC 1990.

“In 1995, the Intergovernmental Panel on Climate Change (IPCC) released its 5-yearly report on climate change [10], in a blaze of publicity, which contained the now infamous phrase that there was “a discernible human influence on global climate”.

Your update reference to “at that time” is vague. The natural interpretation (IMO) is that it refers to the time in 2008 when you diagnosed the provenance. However, in 2007 Connolley diagnosed the attribution to Lamb on wikipedia (see linked page previously by Connolley and myself). You either need to correct the claim that he did not know the source to read that he had noted it resembled a graph by Lamb, or amend the time reference so that it explicitly refers to 2005.

Steve: thanks for clarifying this about Daly. As I mentioned in my previous online comment, in deference to your observation about Connolley, I had amended my comment to say that he had said at his blog that the graphic lacked a “good source”. He made this comment in May 2007, though, as you have observed, other sources (e.g. Climategate) show that Connolley was aware that the graphic derived from Lamb. I’ve added a link to Connolley’s blog post in my update comment. As you are aware, I had linked to Connolley’s blog post in my 2008 commentary where I re-visited and updated the topic.

As I’d said previously, the supposed problem wasn’t on my radar at the time, since I assumed that it came from Lamb somewhere and hadn’t considered the possibility that there was an issue.

As you observe, Connolley at the time was aware that the graphic derived from Lamb though he didn’t say this in his blog post, making his entire line of criticism in the blog post highly disingenuous (to use a Mannian term) – a point that follows logically from your present commentary.

“This time the issue is the 1990 IPCC graph, which McI seems to accept uncritically despite its lack of good source (see wiki for more). TGGWS used the old graph uncritically; this is obviously wrong.”

The link is not carried across in the quote, but linked to the discussion where he indicates the probably Lambian lineage of the graph. Suggesting that he “did not say so” in the blog post is highly misleading, and your inference that he was hypocritical based on the supposition that he hid the evidence relating the graph to Lamb is unwarranted (to say the least).

More directly, his criticism was based on the stark contrast between your obsessive criticism of minor details in graphs that you don’t like compared to your uncritical acceptance of graphs that sell the stock you wish to sell.

You strain at gnats and swallow camels.

Steve: I regularly remind readers not to abandon critical standards merely because they “like” a graph. I presented the IPCC 1990 graphic as an example of what climate scientists thought in 1990. I did not “uncritically accept” it. Please provide a quote evidencing your claim.

The verification r2 of ~0 in the MBH graphic was hardly a “minor detail”. Nor was the fact that it was non-robust to presence/absence of bristlecones. Nor was the benchmarking of the RE statistic.

Tom, your zeal sometimes obstructs careful reading. I didn’t criticize Connolley’s blog post because the Lamb connection was only in the link. I criticized the blog post because his slagging of me for being uninterested in the precise provenance of the IPCC graphic when he knew all along that there was no particular problem with its provenance. If Connolley was satisfied that the IPCC 1990 could be readily traced back to the Lamb graphic, what purpose was served by criticizing me for being uninterested in the supposed lack of “good source”. BTW in my 2008 post on this topic, which I linked, I discuss Connolley’s wiki comments. If you feel that Connolley’s link elsewhere was sufficient, then why are you criticizing me when you would have located a discussion of connolley’s wiki comments if you’d bothered following my link.